1.   Automotive tires have greatly improved in recent years, and tire failures have decreased drastically.

2.   Add hot ambient temperatures and long drives, and you can get tire failure.

3.   But higher pressures also make the ride bumpier and can make a vehicle more likely to roll over, even without a tire failure.

4.   But higher-pressure tires increase the risk that sport utility vehicles will roll over during some driving situations without tire failure.

5.   But the agency is not looking at driver behavior or at the Explorer in its investigation of the tire failures.

6.   But the type of tire failure occurring on Firestone tires seems particularly likely to happen at high speeds, and rollovers are especially likely at high speeds.

7.   Calculating the frequency of rollovers when tires fail is almost impossible because no one knows for sure how many tire failures there are.

8.   Firestone contends that many tire failures occur because customers fail to keep tires properly inflated.

9.   Extensive heat on passenger-car tires also makes them soft, but for more prolonged driving, that means tire failure.

10.   First, any conscientious driver should feel some sort of vibration or unusual sensation through the steering wheel when tire failure takes place.